Articles of Footwear

ABSTRACT

An article of footwear including a footwear upper and a sole assembly secured to the footwear upper. The sole assembly has a forefoot portion and a heel portion, and includes an outsole, a midsole disposed on the outsole and an instability insert disposed between the outsole and the midsole in the forefoot portion of the sole assembly. The instability insert causes a forefoot protrusion to be defined by the outsole in the forefoot portion of the sole assembly.

TECHNICAL FIELD

This disclosure relates to articles of footwear having forefoot cushioning.

BACKGROUND

Articles of footwear, such as shoes, are generally worn while exercising to protect and provide stability of a user's feet. In general, shoes include an upper portion and a sole. When the upper portion is secured to the sole, the upper portion and the sole together define a void that is configured to securely and comfortably hold a human foot. Often, the upper portion and/or sole are/is formed from multiple layers that can be stitched or adhesively bonded together. For example, the upper portion can be made of a combination of leather and fabric, or foam and fabric, and the sole can be formed from at least one layer of natural rubber. Often materials are chosen for functional reasons, e.g., water-resistance, durability, abrasion-resistance, and breathability, while shape, texture, and color are used to promote the aesthetic qualities of the shoe.

SUMMARY

One aspect of the disclosure provides, an article of footwear including a footwear upper and a sole assembly secured to the footwear upper. The sole assembly has a forefoot portion and a heel portion, and includes an outsole, a midsole disposed on the outsole and an instability insert disposed between the outsole and the midsole in the forefoot portion of the sole assembly. The instability insert causes a forefoot protrusion to be defined by the outsole in the forefoot portion of the sole assembly.

Another aspect of the disclosure provides, an article of footwear including a footwear upper and a sole assembly secured to the footwear upper. The sole assembly has a forefoot portion and a heel portion. The forefoot portion of the sole assembly is configured to provide a first period of instability upon receiving the weight of a user followed by a second period of stability.

Implementations of the disclosure may include one or more of the following features. In some implementations, the heel portion is configured to at least partially collapse upon receiving the weight of a user and cause the user to rotate the sole assembly forward, placing the weight of the user on the forefoot portion of the sole assembly. In some implementations, the sole assembly includes an outsole, a midsole disposed on the outsole and an instability insert disposed between the outsole and the midsole in the forefoot portion of the sole assembly, the instability insert causing a forefoot protrusion to be defined by the outsole in the forefoot portion of the sole assembly.

In some implementations, the forefoot portion of the outsole defines a radius of curvature of between about 130 mm and about 190 mm (preferably about 160 mm). The forefoot protrusion can have a height, measured from a lowest point of the protrusion to an outer edge of the outsole, of between about 4 mm and about 12 mm (preferably about 8 mm). The instability insert may define a substantially elliptical shape in top and side views. In some examples, the instability insert has a thickness of between about 3 mm and about 9 mm (preferably about 6 mm), a length of between about 65 mm and about 85 mm (preferably about 76 mm), and a width of between about 45 mm and about 55 mm (preferably about 50 mm). The instability insert may comprise polyurethane. In some implementations, the instability insert has a durometer of between about 15 Asker C and about 20 Asker C.

In some implementations, the article of footwear includes a heel insert disposed substantially between the outsole and the midsole in the heel portion of the sole assembly, the heel insert configured to collapse under a user's weight. The heel insert may comprise at least one of polyurethane and a ethylene-vinyl-acetate copolymer (EVA). In some examples, the heel insert has a durometer of between about 42 Asker C and about 48 Asker C and/or a thickness of between about 10 mm and about 35 mm.

The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIGS. 1 and 2 are front perspective views showing the left component of a pair of shoes.

FIG. 3 is a rear view showing the left component of a pair of shoes.

FIGS. 4 and 5 are rear perspective views showing the left component of a pair of shoes.

FIG. 6 is a top perspective view showing the left component of a pair of shoes.

FIG. 7 is a bottom view of a sole assembly for a left component of a pair of shoes.

FIG. 8 is a top view of the sole assembly of FIG. 7.

FIG. 9 is a side view of the sole assembly of FIG. 7.

FIG. 10 is a section view of the sole assembly of FIG. 7 along line 10-10.

FIG. 11 is a side view of the sole assembly of FIG. 7.

FIG. 12 is a rear view of the sole assembly of FIG. 7.

FIG. 13 is a section view of the sole assembly of FIG. 7 along line 13-13.

FIG. 14 is a section view of the sole assembly of FIG. 7 along line 14-14.

FIG. 15 is a section view of the sole assembly of FIG. 7 along line 15-15.

Like reference symbols in the various drawings indicate like elements. By way of example only, all of the drawings are directed to an article of footwear (e.g., shoe) suitable to be worn on a user's left foot. The invention includes also the mirror images of the drawings, i.e. an article of footwear suitable to be worn on the infant's right foot.

DETAILED DESCRIPTION

FIGS. 1-6 illustrate an exemplary article of footwear 100 configured to promote muscle activity in various areas of the user's body, such as the gastrocnemii (calves), quadriceps (thighs), and glutaeus maximus (buttocks), while walking or running. While wearing each article of footwear 100, the user generally tries to maintain a balanced posture, which promotes greater muscle activity (and optionally fat burning). The article of footwear 100 (e.g., shoe, sandal, boot, etc.) includes a footwear upper 110 and a sole assembly 200 secured to the footwear upper 110. The footwear upper 110 and the sole assembly 200 together define a void 120 configured to securely and comfortably hold a human foot. Although a shoe is shown as an exemplary article of footwear 100, the sole assembly 200 may be used for other types of articles of footwear, including, but not limited to boots, sandals, flip-flops, etc.

The footwear upper 110 may be stitched and/or bonded (e.g., by an adhesive) to the sole assembly 200. The footwear upper 110 may be constructed of one or more leathers, textiles, non-woven materials, and any other suitable material for receiving and holding a user's foot. In some examples, the footwear upper 110 includes moisture-wicking materials.

Referring to FIGS. 7-15, the sole assembly 200 provides a subtle instability that encourages the user's body to work harder to adapt and maintain a balanced gait relative to a generally stable sole assembly, thereby promoting muscle activity. Referring to FIGS. 3-10, the sole assembly 200 has a forefoot portion 202 and a heel portion 204, and includes an outsole 210 and a midsole 220. The outsole 210 and midsole 220 each have a respective forefoot portion 212, 222 and a respective heel portion 214, 224 corresponding to the forefoot portion 202 and the heel portion 204 of the sole assembly 200. In some examples, such as FIGS. 10, 14 and 15, the outsole 210 has a thickness T_(o) of between about 3 mm and about 7 mm (preferably about 5 mm) and the midsole 220 has a thickness T_(m) of between about 3 mm and about 20 mm (preferably about 13 mm). The outsole 210 can be made of natural rubber or formed of a rubber compound including isobutylene rubber, butadiene rubber, styrene butadiene rubber and/or natural rubber. The outsole 210 has a durometer of between about 40 Shore A and about 70 Shore A (preferably 50 Shore A). The midsole 220 can be made of a polyurethane or ethylene vinyl acetate (EVA) and have a durometer of between about 50 Shore A and about 70 Shore A (preferably between about 60 Shore A and about 65 Shore A).

The sole assembly 200 includes an instability insert 230 disposed substantially between the outsole 210 and the midsole 220 in the forefoot portion 202 of the sole assembly 200. The instability insert 230 creates a forefoot protrusion 216 (e.g., a gently domed bulge) in the outsole 210, such that the user experiences a slight rocking (fore-aft and/or side-to-side) in the forefoot portion 202 of the sole assembly. In some examples, the forefoot portion 212 of the outsole 210 defines a radius of curvature R of between about 130 mm and about 190 mm (preferably about 160 mm). The forefoot protrusion 216 may have a height H, measured from a lowest point of the protrusion 216 to an outer edge 218 of the outsole 210, of between about 4 mm and about 12 mm (preferably about 8 mm). The user generally exerts relatively more energy to maintain balance and over-come the instability caused by the instability insert 230, as compared to that experienced while wearing a conventional stable shoe.

In some implementations, the instability insert 230 defines an elliptical shape in top and side views, as shown in FIGS. 8, 10 and 13. In some examples, the instability insert 230 has a thickness T_(i) of between about 3 mm and about 9 mm (preferably about 6 mm), a length L_(i) of between about 65 mm and about 85 mm (preferably about 76 mm), and a width W_(i) of between about 45 mm and about 55 mm (preferably about 50 mm). In some implementations, the instability insert 230 is arranged such that a longitudinal axis 235 of the instability insert 230 has an angle β with a transverse axis 205 of the sole assembly 200 of between about 10° and about 30° (preferably about 20°). The instability insert 230 can be made of a polyurethane and have a durometer of between about 10 Asker C and about 25 Asker C (preferably between about 15 Asker C and about 20 Asker C). By having a softer durometer for the instability insert 230 relative to the outsole 210 and the midsole 220, the user initially experiences the instability of the forefoot protrusion 216 caused by the instability insert 230 upon contact between the outsole 210 and the ground. As the user transfers his/her weight onto the shoe 100, the instability insert 230 at least partially collapses between the outsole 210 and the midsole 220, thereby at least partially collapsing (preferably fully collapsing) the forefoot protrusion 216 and allowing the user to experience increased or substantially full stability within the forefoot portion 202 of the sole assembly as the shoe 100 bears the weight of the user. Consequently, as the user proceeds over a surface (e.g., walk or run) while wearing a pair of the shoes 100, the user experiences an initial period of instability while transferring his/her weight onto one of the shoe 100 followed by a period of stability when the respective shoe 100 bears at least some of the weight of the user. For example, the instability insert 230 collapses, thereby collapsing the forefoot protrusion 216 (e.g., such the outsole 210 has a relatively decreased radius of curvature R) upon receiving a threshold load of at least 30 lbs. The instability insert 230 may be configured to collapse or squish under other threshold loads as well (e.g., at least 15 lbs, 50 lbs, etc.), so as to target certain user weight groups. The initial period of instability causes the user to use stabilizing muscles and exert more energy relative to a conventional shoe. A completely unstable shoe, is generally undesirable, thus the period of stability proceeding the period of at least slight instability provides the user with a functional and safe shoe for exercising.

In some implementations, the sole assembly 200 includes a heel insert 240 disposed substantially between the outsole 210 and the midsole 220 in the heel portion 204 of the sole assembly 200, as shown in FIGS. 9-12 and 15. The heel insert 240 can be made of polyurethane or a polyolefin, such as an ethylene-vinyl-acetate copolymer (EVA), and/or have a durometer of between about 25 Asker C and about 55 Asker C (preferably between about 42 Asker C and about 48 Asker C). The heel insert 240 can have a thickness T_(h) (FIG. 15) of between about 10 mm and about 35 mm (preferably about 25 mm). The heel insert 240 not only provides cushioning and comfort for a user, but the relatively soft durometer of the heel insert 240, as compared to the outsole 210 and the midsole 220, allows the heel portion 204 of the sole assembly 200 to at least partially collapse under a user's weight, thereby causing the user to shift his/her weight toward the forefoot portion 202 of the sole assembly 200. As the user shifts his/her weight to the forefoot portion 202 of the sole assembly 200, the user experiences the subtle instability of the forefoot portion 202 (as caused by the forefoot protrusion 216) and exerts relatively more energy and/or uses relatively more muscles to maintain balance. As the forefoot protrusion 216 collapses or subsides due the weight transfer of the user, the user experiences a subsequent period of stability.

The article of footwear 100 may include a foot bed 300 (FIG. 6) secured to the shoe assembly 200 and/or insole 130 in the void 120 defined by the upper 100 and the shoe assembly 200. The foot bed 300 is compliant to conform to and exhibit the shape of the user's foot bottom and portions of outsole 100. The foot bed 300 may be a foam sheet with a woven or non-woven fabric covering the foam sheet.

A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims. 

1. An article of footwear comprising: a footwear upper; and a sole assembly secured to the footwear upper, the sole assembly having a forefoot portion and a heel portion, the sole assembly comprising: an outsole; a midsole disposed on the outsole; and an instability insert disposed between the outsole and the midsole in the forefoot portion of the sole assembly, the instability insert causing a forefoot protrusion to be defined by the outsole in the forefoot portion of the sole assembly.
 2. The article of footwear of claim 1, wherein the forefoot portion of the outsole defines a radius of curvature of between about 130 mm and about 190 mm.
 3. The article of footwear of claim 2, wherein the forefoot portion of the outsole defines a radius of curvature of about 160 mm.
 4. The article of footwear of claim 1, wherein the forefoot protrusion has a height, measured from a lowest point of the protrusion to an outer edge of the outsole, of between about 4 mm and about 12 mm.
 5. The article of footwear of claim 4, wherein the forefoot protrusion has a height, measured from a lowest point of the protrusion to an outer edge of the outsole, of about 8 mm.
 6. The article of footwear of claim 1, wherein the instability insert defines a substantially elliptical shape in top and side views.
 7. The article of footwear of claim 1, wherein the instability insert has a thickness of between about 3 mm and about 9 mm, a length of between about 65 mm and about 85 mm, and a width of between about 45 mm and about 55 mm.
 8. The article of footwear of claim 7, wherein the instability insert has a thickness of about 6 mm, a length of about 76 mm, and a width of about 50 mm.
 9. The article of footwear of claim 1, wherein the instability insert comprises polyurethane.
 10. The article of footwear of claim 1, wherein the instability insert has a durometer of between about 15 Asker C and about 20 Asker C.
 11. The article of footwear of claim 1, further comprising a heel insert disposed substantially between the outsole and the midsole in the heel portion of the sole assembly, the heel insert configured to collapse under a user's weight.
 12. The article of footwear of claim 11, wherein the heel insert comprises at least one of polyurethane and a ethylene-vinyl-acetate copolymer (EVA).
 13. The article of footwear of claim 12, wherein the heel insert has a durometer of between about 42 Asker C and about 48 Asker C.
 14. The article of footwear of claim 11, wherein the heel insert has a thickness of between about 10 mm and about 35 mm.
 15. An article of footwear comprising: a footwear upper; and a sole assembly secured to the footwear upper, the sole assembly having a forefoot portion and a heel portion; wherein the forefoot portion of the sole assembly is configured to provide a first period of instability upon receiving the weight of a user followed by a second period of stability.
 16. The article of footwear of claim 15, wherein the heel portion is configured to at least partially collapse upon receiving the weight of a user and cause the user to rotate the sole assembly forward, placing the weight of the user on the forefoot portion of the sole assembly.
 17. The article of footwear of claim 15, the sole assembly comprises: an outsole; a midsole disposed on the outsole; and an instability insert disposed between the outsole and the midsole in the forefoot portion of the sole assembly, the instability insert causing a forefoot protrusion to be defined by the outsole in the forefoot portion of the sole assembly.
 18. The article of footwear of claim 17, wherein the forefoot portion of the outsole defines a radius of curvature of between about 130 mm and about 190 mm.
 19. The article of footwear of claim 18, wherein the forefoot portion of the outsole defines a radius of curvature of about 160 mm.
 20. The article of footwear of claim 17, wherein the instability insert has a thickness of between about 3 mm and about 9 mm, a length of between about 65 mm and about 85 mm, and a width of between about 45 mm and about 55 mm.
 21. The article of footwear of claim 20, wherein the instability insert has a thickness of about 6 mm, a length of about 76 mm, and a width of about 50 mm.
 22. The article of footwear of claim 17, wherein the instability insert comprises polyurethane.
 23. The article of footwear of claim 17, wherein the instability insert has a durometer of between about 15 Asker C and about 20 Asker C.
 24. The article of footwear of claim 15, further comprising a heel insert disposed substantially between the outsole and the midsole in the heel portion of the sole assembly, the heel insert configured to collapse under a user's weight.
 25. The article of footwear of claim 24, wherein the heel insert comprises at least one of polyurethane and a ethylene-vinyl-acetate copolymer (EVA).
 26. The article of footwear of claim 24, wherein the heel insert has a durometer of between about 42 Asker C and about 48 Asker C. 